ForcefulForeignKey

When force: true is set, It will delete orphaned data before applying the foreign key constraint. Use cautiously!

class AddFKContraint < ActiveRecord::Migration
  def change
    add_foreign_key 'foo', 'bar', force: true
  end
end

Add this line to your application's Gemfile:

gem 'forceful_foreign_key'

tall forceful_foreign_key

The gem is available as open source under the terms of the MIT License.